Given a set of integers S = { a₁, a₂, a₃, ... a_|S| }, we define a function X on S as follows:
X( S ) = a₁ ^ a₂ ^ a₃ ^ ... ^ a_|S|.
(^ stands for bitwise 'XOR' or 'exclusive or')

Given a set of N integers, compute the maximum of the X-function over all the subsets of the given starting set.

Input

The first line of input contains a single integer N, 1 <= N <= 10⁵.
Each of the next N lines contain an integer a_i, 1 <= a_i <= 10¹⁸.

Output

To the first line of output print the solution.

Example

Input:
3
1
2
4

Output:
7